Document Type
Article
Abstract
Radiogenic isotopes of Sr and Nd provide crucial information on chemical and physical erosion processes, therefore used as tracers for fingerprinting the sources of fluvial sediments. Moreover, elemental geochemistry, 87Sr/86Sr and 143Nd/144Nd signatures in silicate fractions of sediments primarily reflect intricate controls of characteristics and provenance of sediment. A suite of sediment samples collected from two rivers of India, Narmada (large) and Netravati (small) were analyzed for elemental concentrations, 87Sr/86Sr and 143Nd/144Nd in silicate as well as acid-leachable fractions. 87Sr/86Sr in acid-leachable sediment fractions from both the rivers (0.7094 ± 0.0002 for Narmada and 0.7158 ± 0.003 for Netravati) showed more radiogenic 87Sr/86Sr in Netravati compared to Narmada indicating influence of source rocks in their watersheds. Weak correlation of sedimentary 87Sr/86Sr and 143Nd/144Nd with Al and Chemical Index of Alteration (CIA) in silicate fraction indicates that isotopic compositions are primarily controlled by their sources and not by chemical weathering in both the rivers. Provenance of sediments in Narmada is dominated by their supply from Deccan deposits with secondary supply from mid-late Proterozoic Vindhyan along with Meso-proterozoic to Mesoarchean TNd ages. Sediments from Netravati reflected signatures of peninsular gneisses DM dominant with gneisses schists and granodiorite along with Paleoarchean TNd ages. Based on variability of DM 87Sr/86Sr and 143Nd/144Nd, present study highlight that sediment supplies from tributaries to the main- stream in Narmada is inadequate as compared to that in Netravati. 87Sr/86Sr and 143Nd/144Nd signatures in Narmada and Netravati are comparable with Global Rivers.
Disciplines
Environmental Sciences | Fresh Water Studies | Geology
Recommended Citation
Pradhan, S., J. Zhang, M. Baskaran, P. V. Shirodkar, Y. Wu, and U. K. Pradhan (2017), Investigations of the spatial and temporal variations of Sr and Nd isotopes in sediments from two Indian Rivers: Implications to source identification, Geochem. Geophys. Geosyst., 18, 1520–1536, https://doi.org/10.1002/2016GC006669.
Comments
This research was supported by National Natural Science Foundation of China grant 41021064. © 2017 American Geophysical Union, originally published in Geochemistry, Geophysics, Geosystems (https://doi.org/10.1002/2016GC006669). Shared here in compliance with publisher policy under a Creative Commons Attribution License (CC BY 4.0, http://creativecommons.org/licenses/by/4.0/).